The invention concerns a method for collecting and removing runoff water from the inner arc of the strand guide of a beam blank casting machine, in which the cast strand is solidified, and the necessary heat dissipation is achieved by, among other means, sprayed water, during which operation, runoff water can possibly collect on the inner arc of the strand, this runoff water is collected and sucked up with the use of a suction head, and the water-air mixture that is sucked up is separated into water and air. The invention also concerns a device for carrying out this method.
In beam blank or rail blank casting machines, the cast section is solidified within the strand guide. An outer, solid strand shell already solidifies in the mold by heat conduction to water-cooled copper plates. The beam blank preliminary section is produced in a casting radius.
Further heat dissipation is achieved within the strand guide by roller contact, overspray water, and heat radiation. Excess or runoff water basically collects on the inner arc of the strand and accumulates in greater and greater amounts in the direction of strand offtake as each row of nozzles is passed.
On the one hand, the accumulated water hinders heat transfer by spray cooling, and, on the other hand, it would lead to accumulation of water in front of the oxygen-cutting machine if it were not removed from the web of the strand or the web of the beam blank.
The present state of the art is characterized, for example, by blowing out the water from the inner arc of the strand by compressed air. This blowing requires the use of a large amount of power and is associated with high maintenance costs for the compressors needed to produce the required amounts of compressed air. Furthermore, the uncontrolled water blown over the flange edges of the beam blank preliminary section damages the quality of the section that is produced, which can cause material losses.
The removal of web water from beam blanks by suction is basically already known from the document JP 58[1983]-157,559 A1. According to this document, excess water is picked up by a blade-shaped intake suction tube and sucked out by negative pressure at the end of a discharge tube with a round cross section. The negative pressure is produced by a concentric jacketed tube, by means of which air under pressure flows past the end of the discharge tube, with which it interacts to produce the negative pressure. However, the pressure difference is relatively small and only allows residual cooling water to be sucked up. In addition, an oblique surface for diverting excess cooling water is mounted above the intake suction tube and splits into opposite transverse directions above the intake suction tube, so that residual cooling water runs off to both sides of the cast strand and must be collected separately.
Beam blank sections or blank strands, such as beam blanks or rail blanks, are basically shaped in such a way that residual amounts of water cannot independently flow off over the lateral flange edges. Because the space conditions are already very confined by the conditions in the cooling chamber and within the strand guide, there is not enough room to allow the installation of complicated devices for removing the web water. Diverting the water by suitable devices for feeding it into suction tubes is made extremely difficult by the continuously moving rough strand surface.
The document DE 101 22 833 A describes a suction device for secondary water in blank continuous casting machines. The suction device has a flat suction tube mouthpiece that corresponds to the width of the strand and is operated under negative pressure. A separator for collecting the residual water and impurities that have been sucked in is connected in the exhaust air suction line after the suction tube mouthpiece in the direction of flow.